Combinatorial processing enables rapid evaluation of semiconductor processes. The systems supporting the combinatorial processing are flexible to accommodate the demands for running the different processes either in parallel, serial or some combination of the two.
Some exemplary semiconductor wet processing operations include operations for adding (electro-depositions) and removing layers (etch), defining features, preparing layers (e.g., cleans), etc. Similar processing techniques apply to the manufacture of integrated circuits (IC) semiconductor devices, flat panel displays, optoelectronics devices, data storage devices, magneto electronic devices, magneto optic devices, packaged devices, and the like. As feature sizes continue to shrink, improvements, whether in materials, unit processes, or process sequences, are continually being sought for the deposition processes. However, semiconductor companies conduct R&D on full wafer processing through the use of split lots, as the deposition systems are designed to support this processing scheme. This approach has resulted in ever escalating R&D costs and the inability to conduct extensive experimentation in a timely and cost effective manner. Combinatorial processing as applied to semiconductor manufacturing operations enables multiple experiments to be performed on a single substrate.
During combinatorial experiments the substrate surface may be exposed to the ambient environment. In some instances, exposure to the ambient environment may cause a passivating layer to form over the substrate surface. This is observed, for instance, with polysilicon whose surface reacts spontaneously with the ambient environment to form a native oxide layer. Typically, this native oxide layer etches at a markedly different rate than the bulk of the material. This convolutes the determination of the bulk material's true etch rate especially when etching the bulk material with the native oxide layer with a relatively dilute etchant at a relatively low temperature. It is within this context that the embodiments arise.